Screening apparatus



' Nov, 26, 1940.

O O O O O O O O J. I BAXTER, JR 2,222,760

SCREENING APPARATUS Filed Dec; 8, 1937 2 Shets-Sheet 1 IIIIIIIIII IIIIIIII INVENTOR 6% ATTORNEY Nov. 26, 1940. J. BAXTER, JR

SCREENING APPARATUS Filed Dec. 8, 1937 2 Sheets-Sheet 2 Patented Nov. 26, 1940 UNITED STATES SCREENING APPARATUS JosephBaxter, In, Franklin, Ohio, lleigncr to The Black-Clawcon Company, Hamilton, Ohio,

a corporation of Ohio Application December 8, 1937, Serial N0. 178,828

7 Claims.

invention relates to screening apparatus. One object of the invention is the provision of a screening apparatus adapted to screen paper pulp and other fluid material, and which is so arranged as to be capable of screening comparatively large quantities oi material in a structure which is oi comparatively small size and in which an eflective screening action is produced.

Another object or the invention is the provision of a screen or the character mentioned. in which the screen plates are so arranged as to be selfcleaning and so that they may be washed without shutting down or removing any parts.

Another object 012 the invention is the provision of a screening apparatus which produces cleaner stock by effectively screening the desired constituents while the heavier impurities are caused to travel so that they are kept from entering the perforations or slots in the screen Plates.

Another object or the invention is the provision of a. screen for paper pulp stock and the like in in which a substantially vertical screen is located between outer and inner walls, the screen 5 dividing the space between the walls into horizontally juxtaposed discharge and supply chambers ior screened and unscreened material respectively.

Another object of the invention is the provision of a screening apparatus having a vibratable container wall and a fixed material retaining wall, with a substantially vertically extending screen arranged between these walls.

Another object of the invention is the provision or a screening apparatus of the character mentioned in which compressible or yielding means are provided at one side of the movable or vibratory wall, the screen plates being held against such means. in flxed position.

0 Another object of the invention is the provision oi a screening apparatus of the character mentioned in which the inner container wall is vibrated in an oscillatory manner-and with relation to a fixed annular screen.

Another object or the invention is the provision.

01' a screening apparatus having inner and outer walls and a screen provided between the walls and extending substantially vertically, the con- V struction being such that the fluid entering the supplyingchamber oi the screening apparatus gives a circulating or whirling action to the liquid on the supply side oi the screen.

Another object 01' the invention is the provision of a screening apparatus of the character men- ;s tioned certain parts or which are relatlvely'adiustable so that the inlet pipe and the discharge pipe for the unscrcened and screened material may be relatively positioned at desired locations.

Other objects and advantages of the invention will be apparent from the iollowing description, 5 the appended claims and the accompanying drawings in which Fig. 1 is a side elevation oi a screening apparatus embodying the present invention;

Fig. 2 is a top plan view 01 the screening appa m ratus, a portion being shown in horizontal section;

Fig. 3 is a vertical sectio'non the line 3-4 oi Fig.

Fig. 4. a a section on the line M of Fig. is

Fig. 5 is an enlarged sectional view on the line 8-5 of Pig. 3, showing the eccentric adjustment;

Fig. 6 is a section on the line E S of Pig. 5; and

Fig. is a fragmentary perspective view showg g ing the arrangement of the motor support.

The screening apparatus herein shown is one adapted to screen paper pulp and the stud supplied to paper machines for the removal oi uncle sired impurities and for holding back stock pieces as that have not been reduced to the desired fineness. However it will be apparent that the appsratus may be used tor screening other kinds of fluid material.

Referring more particularly to the drawings m by reference numerals, the screening apparatus, which is designated generally by the reference numeral I 0, comprises a base member H, having a chamber I! for receiving the screened stock. At one side of the base member is a discharge g5 conduit ll which communicates with the chamber l2. The base member H has an upstanding wall I 3 which is preferably flanged as indicated at H, and which supports an annular fluid retalning wall or drum ll projecting upwardly o therefrom. The wall I I may be made of sheet metal suitably formed to provide an outwardly extending flange I 8 at its lower end which seats on the flange I 4 oi the base. The two flanges are provided with a number of equally distant holes spaced annularly so that the wall I! may be 10- cated on the base in any desired position, and secured thereto by mean of the attaching bolts I! which extend through the two flanges.

Within the wall II is an annular container 50 wall or drum 1|. and provided between the walls ii and II is a screen shown in the form 0! an annular. series of vertically extending screen plates 2| arranged and to end, and dividing the space between the two walls I! and Ill into an outer receiving supply chamber 23 and an inner chamber at for the screened material. The material to be screened is supplied to the outer annular chamber 23 through a supply passage 26 which is preferably located about midway between the top and bottom of the wall I5, and which is arranged tangentially as shown in Fig. 2 so that the fluid entering'the supply chamber 23, which extends continuously around the screen, is given a whirling rotation in the direction of the arrow indicated in Fig. 2. This fluid supply passage 26 may be coupled to suitable sul ply pipes, and in view of the fact that the wall I5 may be mounted in any desired position on the base member it will be apparent that the fluid suppl passage 25 may be located in close proximity to the fluid discharge conduit i8, or may be located on the other side of the screen or in any other position as may be most desirable for any particular installation.

The wall 29 of the screening apparatus, which is preferably of sheet metal, is given an oscillatory motion in a horizontal direction so that every part of this wall travels in a curved or circular path. The eccentric moving means for the wall M will be later described. The screen plate itself, however, is stationary, the oscillatory movement of the movable wall 2!] producing a rapid change in the pressure of the" liquid in the chamber 2d and increasing the efiectiveness of the screen because'oi the rapid in and out movenient of the material passing through the screen p ate.

Provided between the screen plates 2i and the inner movable wall so are a series of yielding or compressible partition members preferably formed of rubber or the like, and serving to divide the chamber 25 into a series of segmental portions,- the lower ends of which are all in communication with. the base chamber 12. These rubber walls, as shown at 28 in Figs. 2, 3 and l, extend vertically along the outer side of the wall 2d and their outer vertically extending portions areprovided with opposed angularly related surfaces 29 against which the terminal ends of the screen plates rest, the ends of the screen plates being turned inwardly as indicated at 36 in Fig. 4. The screen plates, which are rigid metal members provided with slots or holes of the desired size from the bottom up to a level about 6 inches or so below the normal level of liquid in the chamber 23, are pressed against the surfaces as of the rubber walls by holding members generally designated 32 and arranged between the outer wall it, the ends of the screen plates, and the rubber walls 28. A single holding means is preferably provided for the adjacent ends of each pair of screen plates. This holding means includes a vertically extending'metal bar 33 having an inwardly extending tongue 34 which fits into a vertical groove 35 in the rubber wall '28. The bar 38 is provided with side inclined walls 36 which fit against the inturned ends 30 of the screen plates, and carried at the top and bottom or the bar 38 are wedge members 13? and 38 having wedge suriaQE inclined downwardly and inwardly and cooperating with the inclined surfaces of fixed wedge blocks 38 and so respectively, arranged at the top and bottom of the wall is opposite the joint between adjacent screen plates. It will be understood that one of these locking devices is provided opposite the adjacent ends of each pair of screen plates, the construction of the drawings showing six such locking means and six screen plates,

with the discharge chamber 24 divided into six segmental portions.

The lower ends of the screen plates 2| fit down into a recess provided at the upper end of a wall M in the base member, the plates being held inwardly against the upstanding wall 65 thus provided,'by means of the wedging holding members above described, suitable rubber strips being provided between the screen plates and the wall and also below the lower ends of the screen plates as indicated at 56 so as to prevent leakage around the lower ends of the screen plates from the supply chamber to the discharge chamber of the screening apparatus and insuring that all of the screened material will flow through the holes in the screen.

The holding members 32, at the upper ends thereof, rotatably support hand wheels 4| which are internally threaded for engagement with threaded T-bolts which project upwardly from the wedge blocks 39 so that when a hand wheel M is turned and screwed down on its T-bolt, the bar 33 is forced downwardly and, by the wedging action produced, is also forced inwardly so as to hold the ends or screen plates 2| against the rubber walls 28. The hand wheel M thus rorms a single operating means for securing or loosening each holding member. When the hand wheels M are turned so as to be free oi the threaded T-bolts on the wedge blocks 88, the holding members can be withdrawn vertically, thus freeing the screen plates so that they may be freely withdrawn in an upward direction. Each screen plate may be separately withdrawn without disturbing the mounting of all of the screen plates.

The lower end of the inner wall as has an iiiwardly extending flange 48 below which is a metal filler ring or. Below the filler ring dl is a rubber ring so of substantial thickness, This ring of rubber is bonded to upper and lower thin metal disks Eli and this composite member is supported on a horizontal flange at extending from the base member as shown in Fig. 3, and the'upper and lower metal, disks are secured as by means of bolts 5d and its to the flange cc and the flange bi respectively. The wall 26 is thus so mounted on the base member as to be capable of a horizontal movement in an eccentric path, the support of the movable wall, however, being such as to prevent leakage between it and the base member. With a rubber ring of yielding rubber. or the like, a total in and out movement of the order of about inch may be given to the wall 20.

The lower ends of all of the seental portions of the discharge chamber at communicate with the chamber M in the base, as previously mentioned, so that the screened stock which is passed horimntally through the screen plates can be taken'ofi through a commondischarge conduit it at the bottom of the apparatus. As the compressible or rubber walls 28 subdivide the dis;- charge chamber 2% into a series of portions which communicate only at their lower ends with the common base chamber l2, it will be apparent that a vibratory movement imparted to the inner wall at will alternately exert compression and suction eflects on the material in the discharge chamber that as the movable wall 20 is oscillated, it will act on all of the screen plates in the same manner so that an even screening action is produced at all portions of the screening surface. Furthermore the compression of the rubber walls 28 produced by an outward movement of the inner wall 28 at any location produces an increase in the width or thickness of these walls 28, augmenting the compressive action of the movable wall 20 in changing the pressure on the discharge side of the screen plates.

The height of the material in the outlet chamber may be controlled by suitable means such as a vertically movable valve member 58 provided in the discharge pipe or conduit as shown in Fig. 3

by means of which the level of material being screened may be raised or lowered to submerge all or any part of the screen plates. As the outlet for the material is considerably above the level of the lowest point in the supply chamber 23 there is a Welling up effect on the stock and a smooth flow takes place through the screen and through the discharge conduit.

The space 51 provided between the upwardly extending walls l3 and 43 of the base member extends annularly below the supply chamber 23 of the screening apparatus, and is in free communication with that chamber and forms a sediment collecting space in which sand and other heavy impurities in the paper stock are retained, and from which these heavy settled impurities may be withdrawn continuously or periodically. To provide for the withdrawal of this collected matter, the base member i2 is provided with an outlet pipe 56 as shown in Figs. 1 and 2, this pipe being adapted for connection with a suitable valved discharge pipe extending to any desired point of disposal. The heavy impurities will readily settle down into the retaining space 57, and in view of the tangential direction in which the stock flows into the supply chamber 23, the whirling mass of stock not only keeps the outer surface of screen plates washed clear of any collection of pulp fibers, but also, by the centrifugal action of the whirling mass, throws the heavy impurities outwardly so that they travel along the inner surface of the wall l5 and are kept away from any rubbing action which would wear away the screen plates themselves.

The operating means by which the inner drum of the screening apparatus is vibrated is adapted to give a rapid vibratory movement in an eccentric path and in horizontal direction. The speed of vibration may be of the order of several hundred complete oscillatory cycles per minute. and since there is no instantaneous re versal of movement of any large mass, the speed of movement may be up to seven hundred oscillatory cycles per minute, or even more than that. This vibratory movement of the inner wall or drum 2!) is obtained from a rotatable motor driven shaft Eli which is supported preferably by means of antifriction bearings 81 and 82 held respectively in an upwardly extending motor supporting standard 83 having three spaced feet, and in a pedestal portion 84 which extends upwardly from the base member H within the movable wall 28. The pedestal portion 88 has three spaced segmental portions on which.

the three feet of the standard 68 are supported.

The upper end of the shaft 88 extends into a pocket 68 and is connected by means of a flexible coupling 61 to the lower end of a shaft 68 which is rotated preferably at a speed of several hundred R. P. M. from the electric motor 88, a gear reduction 18 being provided between the motor shaft and the shaft portion 88 so that the motor may operate 'at an efflcient speed. The motor and the gear reduction are preferably arranged as a unit, removably supported on the top of the supporting standard 83. When the motor and the gear reduction are removed, after loosening the hold-down bolts, not illustrated, the connection between either the shaft or shaft 68 and the flexible coupling permits separation of those parts. The motor supporting standard 53 is also removably attached, by suitable hold-down bolts, to the top of the pedestal portion 64, and when the supporting standard 83 is withdrawn in an upward direction, the shaft and its bearings are pulled along with it, providing access to the space ii in which the driven member of the eccentric drive is retained.

Fixed on the shaft 60 is an eccentric 13 having a circular eccentric surface M. This eccentric, as shown in Figs. Sand. 6,, is preferably so ar ranged that the amount of eccentricity may be adjusted to provide for adjustment of the am plitude of movement of the inner wall 20 of the screening apparatus. The eccentric member 13 is therefore provided with a tapered surface 76, of circular cross-section, which fits on the correspondingly shaped portion 1'! provided 60-- centrically on the shaft 80, the tapered surface 16 being eccentric with respect to the surface 14. At the opposite end of the eccentric member 13 is a ringlike portion l8, having fixed therein a plurality of keys or teeth 19. These teeth 19 which are inclined with respect to the axis of the shaft 80, may be engaged in any of a plurality of grooves or sockets 80 provided in a grooved portion 8! on the shaft. The grooves or sockets in this portion iii are arranged annularly about a center which corresponds to the center of the eccentric portion ll of the shaft. The eccentric member 13 may be relatively moved to the left as viewed in Fig. 5, disconnecting the eccentric surface 18 from the eccentric portion ll of the shaft and disengaging the teeth 79 in order that the eccentric member may be rotatably adjusted on the shaft and then moved endwise to the position shown in Fig. 5. The eccentricity oi the surface l4 can thus be varied. The eccentric member 13 is held in any position. of adjustment by a lock nut 82, see Fig. 3.

The outer surface 85 of the ringdilre member is concentric with the surface T4 of the eccen trio member, surface 85 having a small clearance within plate 92 of a spider 86 which imcludes a plurality of arms, preferably of steei plate, the outer ends of which are welded. or otherwise secured to the inner surface of the wall 20. The plate 82 is provided with three segmental openings of slightly larger size than the three segmental portion of the motor sup porting pedestal 84, through which these pontions of the pedestal extend. The eccentric surface I'll carries the inner race 88 of a ball bear ing, the outer race 89 of which is carried in a cage 8i which is held within ring 90 which is welded or otherwise fixed to the plate 95. of the spider 86. The cage 9! is removable from the ring 98 when withdrawal of the shaft 80 is desired. It must be apparent that as the shaft 88 is rotated, the entire spider is moved eceen trlcally with respect to the axis of shaft 88, and every part of the inner drum M is given a vibratory movement in a horizontal direction.

I meets a lower flinger ring 94 which operates in a small closed pump chamber 95, the action of the flinger ring increasing the pressure of the lubricant in the chamber 95 and forcing the lubricant up through a central passage 96 in the shaft to a discharge opening 91 which leads out into the cage of the upper bearing: 5!. It is thus apparent that the lubricant may thus be continuously circulated through the bearings due to the action of the fhnger ring M and the cascade construction mentioned.

The lighter impurities that float on the top of the material in the supply chamber 28 may be removed periodically through a skim pipe ltd which is provided in the outer wall It at a point near the upper level of the liquid in that chamber. This pipe is provided with an adjustable dam or valve Ml so arranged that normally no.

flow takes place past it. An adjustable hand wheel may be employed to raise or lower the dam llll to control the discharge of thelighter material remaining on the surface of the material.

A suitable cleaning fluid may be supplied under pressure through a cleaning pipe I82, indicated in dotted lines in Fig. 3. When there is no material in the apparatus this cleaning pipe tilt, which is preferably connected with a flexible hose so that it can be entirely removed, may be moved along the inside and the outside of the screen plates as the water or other cleaning agent flowing through the hose is discharged forcibly against the plates. However it is unnecessary that the apparatus cease operations during this cleaning process, for both sides of screen plates are freely accessible from the upper end of the apparatus during operation. vertical positioning of" the screen plates it will be obvious that not only is there substantial i'reedom from the collection of slime on either side, but additionally the construction is such that no air binding of the screen plates can take place. And with a screening apparatus in which there is only a limited surface of the material being screened exposed to the air and with the elimination of any falling flow of the liquid when exposed to air, there is a reduced tendency for the stock being screened to take up any air or to create foam. The apparatus acts effectively as there is a gentle flow of stock through the screen, and as there is a comparatively short length for the stock to travel from any screened plate to the ou let passage i8.

While the'form of apparatus herein described constitutes a preferred embodiment of the invention, it is to be understood that the invention is not limited to this precise form of apparatus,

and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

1. A screen otthe character described comprising an annular stationary container wall and amovable container wall for retaining fluent material, a screen provided between said walls in spaced relation therewith and dividing the space between said walls into discharge and supply chambers forscreened and unscreened material respectively, power means for continuously oscillating said movable wall, and a series of yielding And due to the division walls extending from the movable container wall and connected to the screen.

2. .A screen of the character described comprising an annular stationary container wall and a movable, container wall for retaining fluent material, a screen provided between said walls in spaced relation therewith and dividing the space between said walls into discharge and supply chambers for screened andunscreened material respectively, means supporting said movable wall for eccentric movement, power means for continuously operating said movable wall on its eccentric support, and yielding division walls extending from the movable container wall to the screen and connected to both the screen and the movable container wall.

3. A screen of the character described compris ing an outer annular stationary container wall and an inner movable container wall for retain-' screen.

4. A screen of the character described comprising an annular stationary container wall and a movable container wall for retaining fluent material, a series of substantially vertical rigid screen plates fixed between said walls in spaced relation therewith and dividing the space between said walls into supply and discharge chambers, screen retaining members, one for the two adjacent ends of each pair of screen plates, connecting said plates to the stationary container wall, a series of yielding division walls extending from the yieldable container wall to the screen, and power means for continuously osccillating said movable wall.

5. A screen of the character described comprising an annular stationary container wall and an inner movable container wall for retaining fluent material, a screen extending vertically between said walls in spaced relation therewith and dividing the space between said walls into discharge and supply chambers for screened and unscreened material respectively, power means for continuous oscillating said movable wall, a series of yielding division walis extending from the movable container wall and connected to the screen, and an inlet passage extending tangentially with respect to said stationary wall to provide for rotational flow of the material supplied to the supplychamber. v

6. A screen or the character described comprising an annular stationary container wall and a movable container wall for retaining fluent material, a series of substantially vertical rigid screen plates provided between said walls in spaced relation therewith and dividing the space between said walls into discharge and supply chambers for screened and unscreened material respectively, wedge members corresponding in number to the number of screen plates, each wedge member holding adjacent ends 0! two adjacent-plates to the stationary wall, power means for continuously oscillating said movable wall, and yielding division walls extending from the movable container wall to the screen.

7. A screen of the character described comprising an annular stationary container wall and a movable container wall for retaining fluent material, a screen extending vertically between said walls in spaced relation therewith and dividing the space between said walls into discharge and supply chambers for screened and unscreened material respectively, power means for continuously oscillating said movable wall in a circular orbit, and a series of rubber division walls connected to the screen and extending to the movable container wall.

JOSEPH BAXTER, JR. 

